Execute the file "go.bat". The demo will load. You should see a "Loading..." text top-left. Once the demo has fully loaded, the text will change to "Press any key to continue". Once in the demo, press the F1 key for options.
Hint :
Make sure you enable Free Flight and use the mouse and arrow keys on the num-pad to move around. Then use the F2 and F3 key to toggle both FSAA and Soft Reflectance respectively. Use the UP/DOWN arrow keys to increase/decrease reflectance.